Although the invention is not limited to any particular field of use, it is of particular advantage in the logging industry. Logs are usually carried from the forest to some destination such as a sawmill or railroad station by a log trailer pulled by a log truck. When the trailer has been unloaded at such destination it is usually not pulled behind the truck back up the logging road for its next load of logs, but instead is disconnected from the truck and lifted onto the truck for the trip back. Thus, a log trailer is useful in only one direction of travel and always returns empty.
The empty log trailer is usually lifted onto the truck by a wire rope sling suspended from a crane hook or grapple. Such hook or grapple produces a sharp bend in the upper portion of the sling causing the wire rope to wear out quickly at that point, in view of the fact that the truck and trailer may make several and sometimes many empty return trips every working day depending upon the travel time between the source of the logs and the unloading destination. There is a need to provide some way to extend the working life of such slings so that they will not have to be replaced as frequently as is presently necessary.